Immobilized metal ion affinity chromatography (IMAC) provides the basis for extremely efficient and attractive protein and peptide purification methods, applicable also in cases when other techniques fail. IMA-based chromatography for proteins, introduced in 1975 by our group, ranks among the most powerful methods available for laboratory-scale protein purification and for one-step industrial isolation of histidine-tagged recombinant proteins. However, IMAC is still largely undeveloped. The program serves to expand the application range and promote IMAC further up to the frontier of biochemical separation methods. The program objectives are to: A) synthesize new hydrophilic chelating absorbents, differing in their ligand structures and ligand densities: B) perform exploratory experiments with proteins, peptides and nucleotides using various combinations of metal ions and polymer--fixed ligands in order to find out how absorption selectivity and capacity are affected. C) quantify affinities between the chelating absorbents and selected metal ions of biological interest, as well as between IMA-absorbents, model peptides and proteins in order to shed light on the interplay of molecular forces responsible for IMA of biopolymers and to use the results for optimizing working conditions for IMAC, and D) apply IMA-absorbents for fractionation of proteins and peptides of current interest, including membrane proteins, calcium binding proteins and phosphoproteins.